1. Field of the Invention
The present invention relates to a self-propelled vibratory greensroller, preferably with an infinite ground speed control, for achieving more consistent ball roll distance at a given ground speed and for producing a checkerboard stripe pattern on greens without mowing.
2. Brief Description of the Prior Art
An objective in the maintenance programs at nearly all well-maintained golf courses is to have consistency among the greens as to ball roll distance. Ball roll distance, otherwise known as "green speed," is an important physical characteristic of putting surfaces and is typically measured with a stimpmeter. By Newtonian physics, the distance a ball rolls is inversely proportional to the coefficient of rolling resistance of the surface. The smoother the green, the farther the roll. Even with similar treatment, however, the green speed on a golf course may vary between greens and it would be desirable to have a machine capable of selectively bringing up the ball roll distance on the slower greens so as to have consistency among the greens. For example, if a stimp reading of 10 is considered ideal on a given course and the ball roll distance on a particular green is 8.5, it would be desirable to selectively roll this green in a way that increases the ball roll distance by 18 inches.
Greens are mowed short to eliminate the grain thereby providing a smooth putting surface and improving green speed. This usually means, however, that the grass is cut below its optimum height and rendered more susceptible to some disease. Every time a mower removes leaf tissue, a wound is created through which a pathogen may enter. Plants produce carbohydrates, which are their source of energy, by photosynthesis carried out in the green plant parts. A low cutting height eliminates the grain of the grass but reduces green plant tissue, decreasing photosynthesis and the available carbohydrates used for plant growth. One way to improve the health of the green is to raise the height of the cut but this makes a rougher putting green and reduces green speed. A lightweight rolling, however, can be used to reduce the grain and smooth the green, allowing for skipped mowing and producing a healthier green.
A checkerboard stripe pattern on greens such as delivered by a walk behind mower is showcased on televised golf events and is highly appealing to players. The pattern is produced with a walk-behind mower by making alternate passes across the green in one direction and making a second set of alternate passes at an angle to the first. In some instances, the putting green is groomed with a checkerboard stripe pattern without mowing the grass by pushing the mower across the green in the above-mentioned pattern, the lawn mower reel laying the grain of the grass in the above-mentioned pattern. This practice, however, does not smooth out ball marks or foot prints, leaving the putting green cratered and susceptible to being scalped when it is mowed. Plainly, it would be desirable to have a piece of equipment that would produce a checkerboard pattern while treating the greens in a manner that provides consistency and allows for taller grass.
A greensroller from a triplex greensmower is described in U.S. Pat. No. 5,261,213. A commercially available unit is sold under the registered trademark TRUE-SURFACE by Turfline, Inc. of St. Charles, Mo. The vibratory roller described in the subject patent can be used to provide consistent putting conditions on most greens and can be used after topdressing, aerification, for tournament preparations or for achieving a true, smooth and consistent putting green. While a greensroller as described in the above-mentioned patent can be used to provide a smooth putting green, it is too wide to make a 22" checkerboard stripe pattern like that left by a standard, walk-behind lawn mower. In addition, the triplex mower may leave wheel tracks in the green and it is also difficult to customize the amount of treatment applied to each green so as to equalize the greens.